Toner and developer for developing electrostatic latent image, and image forming process using the same

Abstract

A toner for developing an electrostatic latent image, which comprises toner particles and treated titanium oxide fine particles obtained by coating titanium oxide fine particles with 0.1 to 2.0% by weight, in terms of Al 2 O 3 , of aluminum or Al 2 O 3 and further subjecting the coated particles to surface treatment with a treating agent.

What is claimed is: 
     
       1. A toner for developing an electrostatic latent image, which comprises toner particles and treated titanium oxide fine particles obtained by coating titanium oxide fine particles with 0.1 to 2.0% by weight, in terms of Al 2  O 3 , of aluminum or Al 2  O 3  and further subjecting the coated particles to surface treatment with a treating agent, wherein said surface treatment is carried out using a treating agent selected from the group consisting of an anionic surface active agent, an amphoteric surface active agent, a silane coupling agent and a silicone oil in a solution. 
     
     
       2. The toner according to claim 1, wherein said toner contains said treated titanium oxide fine particles in an amount of from 0.1 to 5.0% by weight based on the weight of the toner. 
     
     
       3. The toner according to claim 1, wherein said treating agent is selected from an anionic surface active agent, an amphoteric surface active agent, a silane coupling agent and a silicone oil. 
     
     
       4. The toner according to claim 3, wherein the amount of said treating agent used in the surface treatment is from 5 to 50% by weight based on said treated titanium oxide fine particles. 
     
     
       5. The toner according to claim 1, wherein said coating comprises: adding a compound selected from the group consisting of aluminum chloride, aluminum sulfate, aluminum nitrate, hydrated alumina, hydrated alumina-silica, hydrated alumina-titania, hydrated alumina-titania-silica and hydrated alumina-titania-silica-zinc oxide to an aqueous solution or solvent;   dipping titanium oxide fine particles in said solution or solvent; and   drying said coated particles.   
     
     
       6. The toner according to claim 3, wherein said treating agent is a silane coupling agent, and said silane coupling agent is used in combination with a fatty acid or a fatty acid ester. 
     
     
       7. A developer for developing an electrostatic latent image, which comprises a resin-coated carrier and a toner, wherein said toner comprises toner particles and treated titanium oxide fine particles obtained by coating titanium oxide fine particles with 0.1 to 2.0% by weight, in terms of Al 2  O 3 , of aluminum or Al 2  O 3  and further subjecting the coated particles to surface treatment with a treating agent, wherein said surface treatment is carried out using a treating agent selected from the group consisting of an anionic surface active agent, an amphoteric surface active agent, a silane coupling agent and a silicone oil in a solution. 
     
     
       8. The developer according to claim 7, wherein said toner contains said treated titanium oxide fine particles in an amount of from 0.1 to 5.0% by weight based on the weight of the toner. 
     
     
       9. The developer according to claim 7, wherein the coating resin of said resin-coated carrier comprises a silicone-modified acrylic resin, a fluoroalkyl acrylate resin or a fluoroalkyl methacrylate resin. 
     
     
       10. The developer according to claim 7, wherein said resin-coated carrier has a volume resistivity of 10 6  to 10 12  Ω.cm at application of 10 3 .8 V. 
     
     
       11. An image forming process comprising the steps of: forming an electrostatic latent image on an electrostatic latent image holder;   developing the electrostatic latent image on the electrostatic latent image holder with a developer held on a developer carrying member disposed so as to face the electrostatic latent image holder, to thereby form a toner image; and   transferring the thus formed toner image to an image-receiving sheet,   wherein said developer comprises toner particles and treated titanium oxide fine particles obtained by coating titanium oxide fine particles with 0.1 to 2.0% by weight, in terms of Al 2  O 3 , of aluminum or Al 2  O 3  and further subjecting the coated particles to surface treatment with a treating agent,   wherein said surface treatment is carried out using a treating agent selected from the group consisting of an anionic surface active agent, an amphoteric surface active agent, a silane coupling agent and a silicone oil in a solution.   
     
     
       12. The image forming process according to claim 11, wherein said toner contains said treated titanium oxide fine particles in an amount of from 0.1 to 5.0% by weight based on the weight of the toner. 
     
     
       13. The image forming process according to claim 11, further comprising charging said developer by a charging member, wherein said charging member comprises a silicone-modified acrylic resin, a fluoroalkyl acrylate resin or a fluoroalkyl methacrylate resin. 
     
     
       14. The image forming process according to claim 13, wherein said toner contains said treated titanium oxide fine particles in an amount of from 0.1 to 5.0% by weight based on the weight of the toner.